Stabilized lead alkyl and aviation gasoline containing it



Oct. 24, '1 E' i E, L. WALTERS STABILIZED LEAD ALKYL AND AVIATION GASOLINE CONTAINING IT Filed May 5, 1942 5 D 000: E .330: d tum c2565 2 4 lnhlbi'i'or Concentration mqfiOO ml lnveni-or: Ernesfi' L. Walkers v Patented Oct. 24, 1944 1 OFFICE STABILIZED LEAD ALKYL AND AVIATION GASOLINE CONTAINING I'I Ernest L. Walters, San Francisco, Calif., minor to Shell Development Company, San Francisco, Calm, a corporation of Delaware Application May 5, 1942, Serial No. 441,876

11 Claims.

This invention deals with improving the storage stability of alkyl lead and leaded aviation gasolines consisting essentially of relatively stable gasoline-type fuels containing added alkyl lead in suflicient quantity materially to reduce their storage stability. More particularly, it deals with the use of 2,4-dimethyl-6-tertiary butyl phenol for stabilizing tetraethyl lead and/or aviation gasolines containing it.

The main purpose of this invention is to produce aviation gasolines having long time storage stabilities.

It is already known that the addition of tetraethyl lead to cracked gasolines reduces the storage stability of the latter. It is also known that tetraethyl lead may have an unfavorable eflect on the storage stability of gasolines which are normally stable, such as straight-run gasolines, alkylate gasolines, substantially saturated gasolines obtained by catalytic cracking or hydroforming blends of such gasolines with isopentane, cyclopentane, toluene, xylenes, paramine, branched chain ethers, etc.

It has in the past been recommended to add various anti-oxidants or gum inhibitors to unstable gasolines to improve their storage stabilities. Among the active inhibitors are particularly alkylated phenols, aromatic amines and hydroxy amines, etc. While many of these inhibitors are highly effective in the matter of increasing the storage stability of gasolines which are unstable in the absence of tetraethyl lead, I have found that these same inhibitors are relatively ineffective in preventing the instability brought about by the addition of tetraethyl lead to fuels which are stable in the absence of tetra- I ethyl lead. Practically all oxidation inhibitors which are unstable in the absence of tetraethyl lead. However, its effectiveness in stabilizing a gasoline fuel stable by itself but which has been rendered unstable by the action of tetraethyl lead, is extremely great.

In the accompanying drawing, the eflectiveness of several of the most potent commercial available inhibitors is compared graphically with that of 2,4-dimethyl-6-tertiary butyl phenol, the effectiveness being depicted by plotting induction period obtained by testing the fuel at 110 C. and pounds of oxygen versus inhibitor concentration in an aviation gasoline consisting of a straight-run petroleum fraction containing 3 cc. of tetraethyl lead per gallon.

Nine curves are shown, representing the following inhibitors:

inhibitor 2,4-dimethyl-6-tertiary butyl phenol. ,4-dimethyi-6-tertiary octyl phenol. Aerobib (product of American Oyanamid and Chemical Corporation). 4-methyi-2, G-ditertiary butyl henol. 807 mono-isoamyl-p-amino p enol. 209g diamyl-gl-phenylene diamine. Alpha napht ol.

Benz 1 are-amino phenol. Alky p enols, boiling range 200220 O. i-tertiary-butyl catechol.

In addition to the inhibitors shown lathe drawing, many others were tested but not shown because of their lesser commercial importance. None of them approached the 2,4-dimethyl-6- tertiary butyl phenol in effectiveness.

It may be noted that i-tertiary butyl catechol is at the bottom of the list being the least eflective. This is particularly interesting in view of the fact that this same 4-tertlary butyl catechoi is one of the most outstanding inhibitors in stabilizing cracked gasoline.

In aviation gasolines, effective amounts of the 2,4-dimethyl-6-tertiary butyl phenol may be quite small and may range from about .0001% to about .1%. In alkyl lead fluid of commerce, suitable amounts vary from about 0.05% to 50%.

I claim as my invention:

1. Stable aviation gasoline consisting essentially of a normally stable saturate gasoline-type fuel "containing an amount of tetraethyl lead sufficient to render it relatively unstable on storage, and a small amount of 2,4-dimethyl-6- tertiary butyl phenol.

2. The gasoline of claim 1 wherein said amount is between .0001% and .1%. r

3. Stabilized tetraalkyl lead fluid containing a small amount of 2,4-dimethy1-6-tertiary butyl phenol. Y I V 4. Stabilized tetraethyl lead fluid containing a relatively small amount of 2,4-dimethyl-6-tertiary butyl phenol.

- 5. The fluid of claim 4, wherein said amount a is between 0.05% and 50%.

8. A normally stable saturate gasoline type fuel which has been rendered potentially unstable by the addition of tetra-alkyl lead fluid, which gasoline contains a stabilizing amount of 2,4-dimethyl-B-tertiary butyl phenol.

7. A minor portion of tetra-alkyl' lead fluid stabilized against deterioration by 2,4-dimetnyl- B-tertiary butyl phenol, said fluid being dissolved in a major portion or an initially stable saturate gasoline.

8. A normally stable saturate gasoline containing an amount of tetra alkyl lead to render it potentially unstable and a stabilizing amount of 2,4-dimethyl-6-tertlary butyl phenol.

9. The gasoline of claim 8 wherein said gasoline is substantially saturated.

10. The gasoline of claim 8 wherein said gasoline is an aviation gasoline.

11. The gasoline of claim 8 wherein the tetra 10 alkyl lead is tetraethyl lead.

ERNEST L. WALTERS. 

